Identification and antigenic characterization of virulence-associated, plasmid-coded proteins of Shigella spp. and enteroinvasive Escherichia coli.

摘要: Seven plasmid-coded polypeptides, designated a through g, were identified by two-dimensional nonequilibrium pH gradient electrophoresis of radiolabeled extracts from minicells virulent Shigella flexneri serotypes 2a and 5 enteroinvasive Escherichia coli O143. These polypeptides deemed to be products 140-megadalton (MDa) virulence-associated plasmids because they not synthesized in which harboring 140-MDa plasmid or carrying an F lac the same incompatibility group. Synthesis these was repressed incubated at 30 degrees C isolated noninvasive opaque colonial variant, even though strains harbored plasmid. Enriched fractions b, c, d obtained S. serotype preparative isoelectric focusing, polyclonal rabbit antisera recognizing each polypeptide raised. able detect cross-reacting antigens 3, sonnei, E. In addition, Western blots minicell O143 indicated that recognized convalescent antiserum monkey infected with 2a. Images